Ball joints have to be pretty bad to squeak. If it's really your ball joints, you're living on borrowed time. But squeaks going over bumps is usually caused by stabilizer bar bushing or end links, or worn control arm bushings.

If the ball joints were that worn, you should be feeling drift and wander in your steering and see some tire wear. If would be hard to keep the vehicle going straight.

Ball joint failure is bad. Like wheel turns all the way out on the freeway, you lose control and hit the rail/ditch at 70mph. Axle rips out from the transmission, suspension/steering gets tweaked/wrecked.. Good way to kill yourself/others.